Our laboratory investigates mechanisms of gene control in mammalian cells and embryos. One of two major projects deals with regulatory functions of adenovirus. Focal point of these studies is the Ela gene which acts as a transcriptional activator and is involved in malignant transformation. Sequences encoding Ela proteins or certain domians of these proteins have been inserted in prokaryotic expression vectors, and Ela proteins have been produced in E. coli. We have begun to microinject these Ela proteins into mammalian cells and to test their activity. This experimentation will enable us to arrive at a functional anatomy of this important set of eukaryotic regulatory factors. In a second project we analyze patterns of integration and expression of selected gene constructs transferred into mouse embryos. We have begun to insert a number of gene constructs, including the P element transposon or the chloramphenicol transferase gene placed under the control of retroviral promoters or a collagen Ia2 promoter, and we have developed new methods to test tissue specificity and developmental timing of expression.